1. Field of the Invention
The present invention relates generally to optics and more particularly, to systems and methods for adaptive optics without use of a beacon at a target.
2. Description of the Related Art
When light travels through the atmosphere, atmospheric turbulence may perturb the amplitude and phase of the propagating light wave(s). Thus, when an output light beam with a relatively well defined intensity pattern (diameter) and wavefront propagates through the perturbed atmosphere, the atmosphere may cause distortions of the beam. These distortions may result in the cross-section of the beam being less defined, and making the wavefront spatially non-uniform. Adaptive optical systems attempt to measure distortions of the wavefront resulting from atmospheric perturbations and to adjust incoming or outgoing light waves by compensating for the wavefront distortions.
Adaptive optics may be used in a variety of fashions. For example, adaptive optics may be used in laser systems to increase a density of laser beam power to such that the density remains relatively high when received at a desired location on a target or a receiver. Adaptive optics may also be used in imaging systems to improve a quality of a detected image and to increase a resolution of an image taken by a receiver.
Conventional adaptive optics system includes the use of a relatively small beacon positioned at or in a vicinity of the target. Light from the beacon is received at the location of the adaptive optics system and is analyzed to determine any changes to the light caused by turbulence in the atmosphere. In some cases, it may be undesirable or difficult to place a beacon at a target. Thus, it is desirable to be able to quantify the distortions of the light wavefronts caused by atmospheric disturbance without use of a localized beacon positioned at the target.